Flattening Boards Wider than Jointer

[Christopher Kurdziel]

I tried doing the trick where you can flatten boards wider than your jointer by removing the guard and then using double stick tape on the part that you jointed to attach it to a flat piece of wood. Then you plane the opposite side flat in the planer and then flip the board over and it should be flat. I tried doing this, but I ended up with twisted boards. This happened with 4 of 4 boards. What could possibly be going wrong.

[Jim Andrew]

I have only a 12" jointer, and have given up on getting something wider, so just rip the wide boards down the middle, flatten them on the jointer, then glue them back together.

[Jake Elkins]

I only have a 6" jointer and 13" lunchbox planer - this has been my setup for ~ 10 years. I tried to use the jointer (similar to your experience) and sleds for the planer with suboptimal results. I just recently made a router sled for big slabs, and have since used that or hand planes for anything over 6". Might take a little more time, but the results speak for themselves.

[Bruce Wrenn]

First, jointer needs to have rabbeting ledge. I add a piece of hard board (double stick tape) to in feed so edge lines up with rabbeting ledge. Lower in feed and have a go at it.

[Wayne Lomman]

Like Jim, I don't work with anything wider than my machines if I can help it. If not, hand plane it enough to be true through the thicknesser. Cheers

[Warren Lake]

had to do lots in the past then started to use a friends jointer after he passed. I had good material hand picked stuff about 10' on an 8" jointer that had to final at just over 9. Joint off both outside edges then flatten the face now as the under 8" remaining flattens out nice. Then through the planer opposite side till flat then flip take the rabbets off. iT also depends on the job lot of stuff id never be using that type of width

[Matt Day]

I've used the OP's method many times on my previous 8" jointer and it worked great.

After you do the first step at the jointer, put a straight edge on the jointed face (check diagonals of jointer area too) and make sure it's flat.

For your "flat piece of wood" that you're using at the planer, use 1/2" mdf as it is uniform thickness and will conform if there happens to be any bow or anything to it.

[Christopher Kurdziel]

I've used the OP's method many times on my previous 8" jointer and it worked great.

After you do the first step at the jointer, put a straight edge on the jointed face (check diagonals of jointer area too) and make sure it's flat.

For your "flat piece of wood" that you're using at the planer, use 1/2" mdf as it is uniform thickness and will conform if there happens to be any bow or anything to it.

This is exactly what I did. I even marked the piece of wood to see that where I ran it over the jointer that the pencil was gone. I guess Ill have to check that part with a straight edge. I was using 1/2" birch ply through the planer then. Could it possibly be that my planer gives awful snipe and that there is a nick that leaves a line down every board? I hand planed the line down, but it was still twisted like crazy.

[Peter Christensen]

There is always more than one way to skin a cat.

One is to joint the full length of the face, then take a hand power plane and raise the front of the sole so only the back touches. Plane diagonally from the jointed half to the raw half to flatten enough to run through the planer.

Another is to flatten one half and then turn the board to do the other half to get it close enough to run through the planer. Takes skill and understanding of how to present twisted, bowed, and cupped to get both halves close to flat.

Remember that using a jointer without the guard is fraught with danger. Jointing without the guard is not for new or inexperienced people.